NEW YORK - When Jerald Spangenberg collapsed and died in the middle of a quest in an online game, his daughter embarked on a quest of her own: to let her father's gaming friends know that he hadn't just decided to desert them.

It wasn't easy, because she didn't have her father's "World of Warcraft" password and the game's publisher couldn't help her. Eventually, Melissa Allen Spangenberg reached her father's friends by asking around online for the "guild" he belonged to.

One of them, Chuck Pagoria in Morgantown, Ky., heard about Spangenberg's death three weeks later. Pagoria had put his absence down to an argument among the gamers that night.

"I figured he probably just needed some time to cool off," Pagoria said. "I was kind of extremely shocked and blown away when I heard the reason that he hadn't been back. Nobody had any way of finding this out."

With online social networks becoming ever more important in our lives, they're also becoming an important element in our deaths. Spangenberg, who died suddenly from an abdominal aneurysm at 57, was unprepared, but others are leaving detailed instructions. There's even a tiny industry that has sprung up to help people wrap up their online contacts after their deaths.

When Robert Bryant's father died last year, he left his son a little black USB flash drive in a drawer in his home office in Lawton, Okla. It was underneath a cup his son had once given him for his birthday. The drive contained a list of contacts for his son to notify, including the administrator of an online group he had been in.

"It was kind of creepy because I was telling all these people that my dad was dead," Bryant said. "It did help me out quite a bit, though, because it allowed me to clear up a lot of that stuff and I had time to help my mom with whatever she needed."

David Eagleman, a neuroscientist at the Baylor College of Medicine in Houston, has had plenty of time to think about the issue.

"I work in the world's largest medical center, and what you see here every day is people showing up in ambulances who didn't expect that just five minutes earlier," he said. "If you suddenly die or go into a coma, there can be a lot of things that are only in your head in terms of where things are stored, where your passwords are."

He set up a site called Deathswitch, where people can set up e-mails that will be sent out automatically if they don't check in at intervals they specify, like once a week. For $20 per year, members can create up to 30 e-mails with attachments like video files.

It's not really a profit-making venture, and Eagleman isn't sure about how many members it has — "probably close to a thousand." Nor does he know what's in the e-mails that have been created. Until they're sent out, they're encrypted so that only their creators can read them.

If Deathswitch sounds morbid, there's an alternative site: Slightly Morbid. It also sends e-mail when a member dies, but doesn't rely on them logging in periodically while they're alive. Instead, members have to give trusted friends or family the information needed to log in to the site and start the notification process if something should happen.

The site was created by Mike and Pamela Potter in Colorado Springs, Colo. They also run a business that makes software for online games. Pamela said they realized the need for a service like this when one of their online friends, who had volunteered a lot of time helping their customers on a Web message board, suddenly disappeared.

He wasn't dead: Three months later, he came back from his summer vacation, which he'd spent without Internet access. By then, the Potters had already had Slightlymorbid.com up and running for two weeks.

A third site with a similar concept plans to launch in April. Legacy Locker will charge $30 per year. It will require a copy of a death certificate before releasing information.

Peter Vogel, in Tampa, Fla., was never able to reach all of his stepson Nathan's online friends after the boy died last year at age 13 during an epileptic seizure.

A few years earlier, someone had hacked into one of the boy's accounts, so Vogel, a computer administrator, taught Nathan to choose passwords that couldn't be easily guessed. He also taught the boy not to write passwords down, so Nathan left no trail to follow.

Vogel himself has a trusted friend who knows all his important login information. As he points out, having access to a person's e-mail account is the most important thing, because many Web site passwords can be retrieved through e-mail.

Vogel joked that he hoped the only reason his friend would be called on to use his access within "the next hundred years or so" would be if Vogel forgets his own passwords.

But, he said, "as Nathan has proven, anything can happen any time, even if you're only 13."